Settings Activity how to navigate back using the arrow at the top

Hi I've created a settings Activity and when I am in the settings menu and press the back button of the phone i get directed to the "home screen" which is correct but when I am pressing the top arrow of the settings menu nothings happends, it seems to be just a button. Please see imgur to see which arrow i mean. Back arrow in the settings activity, press here. I've looked around in the java code and seems to have found the button? All help is appreciated!!

/**
* Binds a preference's summary to its value. More specifically, when the
* preference's value is changed, its summary (line of text below the
* preference title) is updated to reflect the value. The summary is also
* immediately updated upon calling this method. The exact display format is
* dependent on the type of preference.
*
* @see #sBindPreferenceSummaryToValueListener
*/
private static void bindPreferenceSummaryToValue(Preference preference) {
// Set the listener to watch for value changes.
preference.setOnPreferenceChangeListener(sBindPreferenceSummaryToValueListener);

// Bind the summaries of EditText/List/Dialog/Ringtone preferences
// to their values. When their values change, their summaries are
// updated to reflect the new value, per the Android Design
// guidelines.
bindPreferenceSummaryToValue(findPreference("example_text"));